Dyed Howlite - The Turquoise Impostor
Howlite nuggets and tumbled stones that have been dyed a turquoise color. They look like turquoise - but they are not.
Looks Just Like Turquoise
If you have looked at inexpensive gemstone beads, cabochons, and tumbled stones, your eye has probably been drawn to a sky-blue material with a semi-gloss polish that looks exactly like turquoise. Many pieces even have the gray to black veining often seen in genuine turquoise specimens from the Bisbee and Sleeping Beauty mines.
This material probably isn't turquoise. Most likely it is another mineral, howlite, that has been skillfully dyed to colors so similar to turquoise that it fools almost everyone (at least the first time they see it). The gray to black veining aids in the deception.
Take a look at the tumbled stones and dyed nuggets in the photo at right. They look like turquoise but they are really dyed howlite. Now you know to be skeptical when you see a nice blue stone that looks like turquoise.
What is Howlite?
Howlite is a calcium borosilicate hydroxide mineral that is found in evaporite deposits. It usually occurs in layers of gypsum as irregularly-shaped nodules that resemble small heads of cauliflower. These nodules are usually white in color with gray to black veins.
Although not visible to the eye, howlite is a very porous mineral. This porosity enables it to be penetrated by dyes and stained a variety of colors (see photo at right).
An Ore of Boron but Used as a Gemstone
Howlite is an ore of boron; however, a lot of the howlite produced in the United States is used instead as a gemstone. Howlite is a soft mineral - much softer than agate, jasper and other typical gemstone materials. The lower hardness enables it to be shaped and polished with minimal use of labor, abrasives and electricity. This cost savings makes it one of the least expensive materials that can be used to make gemstone beads, cabochons and tumbled stones.
Howlite dyed a variety of colors: blue, yellow, red, green and purple. Dyed howlite is a common find in tumbled stone mixtures. It kicks up the color of the mix and increases sales.
Why is it Dyed?
Howlite is usually dyed because white howlite receives very little attention in the marketplace. Most people think that it is boring. However, when it is dyed to a brilliant or pastel blue, green, red, yellow or purple it catches people's eyes. Although the bright and pastel colors of dyed howlite are not typical of gem materials (and experienced eyes detect the phony color immediately), these dyed stones are exceptionally popular as beads and tumbled stones. They can also be produced at low expense because howlite, with a hardness of 3-1/2, can be tumbled or cut faster and at lower cost than any quartz, agate or jasper.
Dye is what gives howlite its appeal.